// Copyright 2019 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "dawn/wire/WireDeserializeAllocator.h"

#include <algorithm>

namespace dawn::wire {
WireDeserializeAllocator::WireDeserializeAllocator() {
    Reset();
}

WireDeserializeAllocator::~WireDeserializeAllocator() {
    Reset();
}

void* WireDeserializeAllocator::GetSpace(size_t size) {
    // Return space in the current buffer if possible first.
    if (mRemainingSize >= size) {
        char* buffer = mCurrentBuffer;
        mCurrentBuffer += size;
        mRemainingSize -= size;
        return buffer;
    }

    // Otherwise allocate a new buffer and try again.
    size_t allocationSize = std::max(size, size_t(2048));
    char* allocation = static_cast<char*>(malloc(allocationSize));
    if (allocation == nullptr) {
        return nullptr;
    }

    mAllocations.push_back(allocation);
    mCurrentBuffer = allocation;
    mRemainingSize = allocationSize;
    return GetSpace(size);
}

void WireDeserializeAllocator::Reset() {
    // The initial buffer is the inline buffer so that some allocations can be skipped
    mCurrentBuffer = mStaticBuffer;
    mRemainingSize = sizeof(mStaticBuffer);

    for (auto& allocation : mAllocations) {
        free(allocation.ExtractAsDangling());
    }
    mAllocations.clear();
}
}  // namespace dawn::wire
